That "SPC" chart that runs from 6.5 to 8.5 sounds like an arbitrary set-up. Maybe effort should be put towards finding what the product needs. Barring that, I speculate if there is a viscosity problem, it is too low. This condition allows the paste to (one) slump on itseld, and (two) not withstand the hydraulic pressure generated by the squeegee. Watch the temperature dependency/effects on viscosity. Good Luck Bill Keaton [log in to unmask] (507)837-4325 ______________________________ Reply Separator _________________________________ Subject: Re: Stencil design or Solder Paste? Author: [log in to unmask] at internet Date: 4/3/96 8:18 AM I would increase the stencil thickness to 7 mils. With a metal blade, you should not have any "scooping out" of the paste in the aperatures as you would with a polymer blade squeegee. The paste height I generally get using metal blades and stencils is pretty close to the stencil foil thickness. ______________________________ Reply Separator _________________________________ Subject: Stencil design or Solder Paste? Author: [log in to unmask] at Internet Date: 4/3/96 11:37 AM Good day, We have encountered a low solder paste level in the printing process. We are using a Metal squeegee on a Metal Screen to print the solder paste onto the PCB before SMT processes. We were wondering whether the solder paste viscosity is too thick; or there is a Stencil Design fault. The SPC chart states the solder paste thickness should be between 6.5 mil to 8.5 mil. But we can only achieve only up to 6.2 mil of solder paste thickness. Our stencil is 6.0 mil in thickness. Can anyone give me the specifications on the design of Metal Stencils and give suggestions on how to solve the above problems? Thank you. Regards, Chan Yong Kwee E-mail:[log in to unmask] Tel : (65) 746-6617 Pg : 9-490-6514